Back to results
US 6,159,553 AGranted
Thermal barrier coating for silicon nitride
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorsChien-Wei Li, Thomas Edward Strangman
Life of this patent
Estimating the term…
Abstract
A coating of whisker shaped beta silicon nitride grains are formed upon a silicon nitride substrate by sintering over a period of several hours, and the resulting product has a porous reaction bond coating strongly adhered to the silicon nitride substrate.
Claims8
Method of producing a thermal barrier coating for a component subject to thermal stress comprising the steps of:
- (a) providing a silicon nitride substrate;
- (b) applying a composition, said composition including a powder containing silicon nitride, boron nitride and sintering aids, upon said silicon nitride substrate, said powder containing about 70-90 weight percent silicon nitride, about 1-20 weight percent boron nitride, and a balance of sintering aids of oxides of at least one element selected from the group consisting of Sc, Y, La, Mg, Ca, Sr, and Ba;
- and
- (c) drying and sintering the composition produced in accordance with step (b) at temperatures and times sufficient to produce said thermal barrier coating having whisker-shaped beta silicon nitride grains therein.
1 more element
Method of producing a thermal barrier coating for a component subject to thermal stress comprising the steps of:
- (a) providing a silicon nitride substrate;
- (b) applying a composition, said composition being an aqueous slurry and including silicon nitride and sintering aids, upon said silicon nitride substrate, said composition containing 55-74 weight percent silicon nitride, and a balance of sintering aids of oxides of at least one element selected from the group consisting of Sc, Y, La, Mg, Ca, Sr, and Ba;
- and
- (c) drying and sintering the composition produced in accordance with step (b) at temperatures and times sufficient to produce said thermal barrier coating having whisker-shaped beta silicon nitride grains therein.
1 more element
Dependencies are inferred from the claim text.